U.S. patent number 10,777,346 [Application Number 16/615,842] was granted by the patent office on 2020-09-15 for circuit assembly.
This patent grant is currently assigned to AutoNetworks Technologies, Ltd., Sumitomo Electric Industries, Ltd., Sumitomo Wiring Systems, Ltd.. The grantee listed for this patent is AutoNetworks Technologies, Ltd., Sumitomo Electric Industries, Ltd., Sumitomo Wiring Systems, Ltd.. Invention is credited to Toshiyuki Tsuchida, Shigeki Yamane.
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United States Patent |
10,777,346 |
Tsuchida , et al. |
September 15, 2020 |
Circuit assembly
Abstract
A circuit assembly includes: a circuit board; an inductor that
is disposed on the circuit board, and that includes a coil
including a winding portion made by winding a winding wire, and a
core member; and a heat dissipation plate that is disposed on the
opposite side of the surface of the circuit board on which the
inductor is disposed, wherein a through hole is provided in a
region of the circuit board that corresponds to the inductor, and a
receiving protrusion that penetrates the through hole and protrudes
to a surface side of the circuit board on which the inductor is
disposed, and that is in heat transfer contact with the coil and
the core member is provided in a region that corresponds to the
through hole in the heat dissipation plate.
Inventors: |
Tsuchida; Toshiyuki (Mie,
JP), Yamane; Shigeki (Mie, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
AutoNetworks Technologies, Ltd.
Sumitomo Wiring Systems, Ltd.
Sumitomo Electric Industries, Ltd. |
Yokkaichi, Mie
Yokkaichi, Mie
Osaka-Shi, Osaka |
N/A
N/A
N/A |
JP
JP
JP |
|
|
Assignee: |
AutoNetworks Technologies, Ltd.
(Yokkaichi, Mie, JP)
Sumitomo Wiring Systems, Ltd. (Yokkaichi, Mie,
JP)
Sumitomo Electric Industries, Ltd. (Osaka-Shi, Osaka,
JP)
|
Family
ID: |
1000005056305 |
Appl.
No.: |
16/615,842 |
Filed: |
May 9, 2018 |
PCT
Filed: |
May 09, 2018 |
PCT No.: |
PCT/JP2018/017879 |
371(c)(1),(2),(4) Date: |
November 22, 2019 |
PCT
Pub. No.: |
WO2018/216465 |
PCT
Pub. Date: |
November 29, 2018 |
Prior Publication Data
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|
|
|
Document
Identifier |
Publication Date |
|
US 20200194160 A1 |
Jun 18, 2020 |
|
Foreign Application Priority Data
|
|
|
|
|
May 24, 2017 [JP] |
|
|
2017-102465 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05K
1/181 (20130101); H05K 1/115 (20130101); H05K
1/0203 (20130101); H01F 27/24 (20130101); H01F
27/2823 (20130101); H01F 27/06 (20130101); H01F
2027/065 (20130101); H05K 2201/1003 (20130101); H05K
2201/066 (20130101) |
Current International
Class: |
H05K
1/18 (20060101); H01F 27/06 (20060101); H01F
27/24 (20060101); H01F 27/28 (20060101); H05K
1/11 (20060101); H05K 1/02 (20060101) |
Foreign Patent Documents
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|
|
|
|
|
|
S52-019655 |
|
Feb 1977 |
|
JP |
|
H07-094342 |
|
Apr 1995 |
|
JP |
|
H10-199731 |
|
Jul 1998 |
|
JP |
|
2013-149943 |
|
Aug 2013 |
|
JP |
|
2016-152349 |
|
Aug 2016 |
|
JP |
|
Other References
International Search Report, Application No. PCT/JP2018-017879,
dated Aug. 7, 2018. ISA/Japan Patent Office. cited by
applicant.
|
Primary Examiner: Norris; Jeremy C
Attorney, Agent or Firm: Honigman LLP
Claims
The invention claimed is:
1. A circuit assembly comprising: a circuit board; an inductor that
is disposed on the circuit board, and that includes a coil
including a winding portion made by winding a winding wire, and a
core member; a heat dissipation plate that overlaps the opposite
side of the surface of the circuit board on which the inductor is
disposed; and an insulating frame that is positioned with respect
to the circuit board, wherein the frame integrally includes a
subframe that includes side walls that surround at least a part of
the inductor, and a bottom wall that continues to the side walls,
and that is disposed between the inductor and the circuit board in
a state separated from the circuit board, a board side through hole
is provided in a region of the circuit board that corresponds to
the inductor, and a frame side through hole is provided in a region
of the bottom wall that corresponds to the board side through hole,
and a receiving protrusion that penetrates the board side through
hole and the frame side through hole, that protrudes to a surface
side of the circuit board on which the inductor is disposed, and
that is in heat transfer contact with the coil or the core member
is provided in a region of the heat dissipation plate that
corresponds to the board side through hole.
2. The circuit assembly according to claim 1, wherein the coil is
disposed so that the axis of the winding portion extends along the
circuit board, and the receiving protrusion has a shape extending
along a side surface that extends along the axis of the winding
portion, and is in heat transfer contact with the side surface.
3. The circuit assembly according to claim 1, wherein a filler is
provided between the receiving protrusion and the coil or the core
member.
4. The circuit assembly according to claim 1, wherein a cushioning
material is provided between the receiving protrusion and the coil
or the core member.
5. The circuit assembly according to claim 2, wherein a filler is
provided between the receiving protrusion and the coil or the core
member.
6. The circuit assembly according to claim 2, wherein a cushioning
material is provided between the receiving protrusion and the coil
or the core member.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is the U.S. national stage of PCT/JP2018/017879
filed on May 9, 2018, which claims priority of Japanese Patent
Application No. JP 2017-102465 filed on May 24, 2017, the contents
of which are incorporated herein.
TECHNICAL FIELD
The technique disclosed in this specification relates to a circuit
assembly.
BACKGROUND
A circuit assembly in which a circuit board and a heat dissipation
plate that dissipates the heat generated in the circuit board to
the outside overlap each other is known.
In such a circuit assembly, if a metal bus bar is disposed on the
back side of the circuit board (the surface on which the heat
dissipation plate is placed), the heat generated from the
electronic components mounted on the circuit board is relatively
efficiently transferred to the heat dissipation plate via the bus
bar, which has high heat conductivity, and is dissipated to the
outside. However, if no bus bar is disposed, the heat generated
from the electronic components is difficult to be transferred to
the heat dissipation plate, and thus the temperature of the circuit
assembly and the inside of the apparatus accommodating the circuit
assembly may become high.
Also, like the conventional coil described in JP H7-94342A, if a
base made of synthetic resin is provided between a circuit board
and a core, heat conductivity to a heat dissipation plate may
further decrease, the temperature inside the case of the apparatus
may become high, and the performance of electronic components may
deteriorate.
The technique disclosed in the present specification has been
completed based on the above-mentioned circumstances, and an object
is to provide a circuit assembly having excellent heat
dissipation.
SUMMARY
The technique disclosed in the present specification is a circuit
assembly including: a circuit board; an inductor that is disposed
on the circuit board, and that includes a coil including a winding
portion made by winding a winding wire, and a core member; and a
heat dissipation plate that is disposed on the opposite side of the
surface of the circuit board on which the inductor is disposed,
wherein a through hole is provided in a region of the circuit board
that corresponds to the inductor, and a receiving protrusion that
penetrates the through hole and protrudes to a surface side of the
circuit board on which the inductor is disposed, and that is in
heat transfer contact with the coil and the core member is provided
in a region of the heat dissipation plate that corresponds to the
through hole.
In this configuration, the receiving protrusion provided on the
heat dissipation plate protrudes from the through hole of the
circuit board. Accordingly, the receiving protrusion can be in heat
transfer contact with the coil or the core member at a position
close to the coil or the core member that is a heat generating
member. As a result, the heat generated from the coil and the core
member can be efficiently transferred to the heat dissipation
plate, and can be dissipated to the outside.
The above circuit assembly may also have the following
configurations.
The coil may be disposed so that the axis of the winding portion
extends along the circuit board, and the receiving protrusion may
be in a shape extending along a side surface that extends along the
axis of the winding portion, and may be in heat transfer contact
with the side surface.
In this way, according to the configuration in which the coil is
disposed vertically with respect to the circuit board, the area
required for the coil on the circuit board can be reduced, as
compared with a so-called horizontal configuration in which the
coil is disposed in a direction in which the axis of the winding
portion intersects the circuit board. As a result, the circuit
assembly can be made more compact.
In addition, because the receiving protrusion is shaped along the
side surface that extends along the axial direction of the winding
portion of the coil disposed vertically, even if the side surface
is not flat, the entire facing surface can be disposed close to the
side surface. Accordingly, the circuit assembly is excellent in
heat dissipation.
In the vertically disposed coil, if the side surface of the winding
portion is not flat, there is a concern about rattling due to
vibration, compared to the horizontally disposed coil. However, the
receiving protrusion that is shaped along the side surface of the
winding portion can stably support at least a part of winding
portion from the circuit board side. Therefore, rattling of the
coil can be reduced.
A filler such as grease or a heat dissipation agent may also be
provided between the receiving protrusion and the coil or the core
member. Alternatively, a cushioning material such as a heat
dissipation sheet may also be provided. With this configuration,
even if there is a tolerance on the contact surface between the
receiving protrusion and the coil or the core member, and there is
a gap, the receiving protrusion and the coil or the core member can
be reliably contacted in terms of heat transfer. As a result, a
circuit assembly having a more excellent heat dissipation effect
can be obtained.
Advantageous Effects
According to the technique disclosed in the present specification,
a circuit assembly having excellent heat dissipation can be
obtained.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view of a circuit assembly according to a
first embodiment.
FIG. 2 is a plan view of the circuit assembly.
FIG. 3 is an elevation view of the circuit assembly.
FIG. 4 is a right side view of the circuit assembly.
FIG. 5 is a cross sectional view taken along line A-A of FIG.
2.
FIG. 6 is a perspective view of an inductor.
FIG. 7 is a perspective view of a heat sink.
FIG. 8 is a plan view of the heat sink.
FIG. 9 is a partially enlarged side view of the heat sink.
FIG. 10 is a perspective view of a frame.
FIG. 11 is a plan view of the frame.
FIG. 12 is a right side view of the frame.
FIG. 13 is a plan view of a circuit assembly according to a second
embodiment.
FIG. 14 is a cross sectional view taken along line B-B of FIG.
13.
FIG. 15 is a perspective view of a heat sink.
FIG. 16 is a plan view of the heat sink.
FIG. 17 is a partially cutaway perspective view of a frame.
FIG. 18 is a plan view of the frame.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
First Embodiment
The first embodiment will be described with reference to FIGS. 1 to
12. A circuit assembly 10 of the present embodiment is disposed
between a power source such as a battery and on-board electrical
components such as a lamp and a motor, and is accommodated in a
case of an electrical junction box that performs connection and
disconnection of power supplied from the power source to the
on-board electrical components. In the following description, the
upper side in FIG. 5 is described as the front side or the upper
side, and the lower side is described as the back side or the lower
side. Also, the lower side in FIG. 2 is described as the front, the
right side as the right, and the left side as the left.
As shown in FIGS. 1 and 5, the circuit assembly 10 includes a
circuit board 11, a heat sink 40 (an example of a heat dissipation
plate) that is disposed on the back side (the lower surface in FIG.
5) of the circuit board 11, and a frame 60 that is positioned with
respect to the circuit board 11.
Circuit Board 11
The circuit board 11 includes a conductive circuit (not shown)
formed on an insulating substrate by a printed wiring technique,
and inductors 20 and a plurality of other electronic components
mounted at predetermined positions of the conductive circuit. The
plurality of electronic components including the inductors 20 are
disposed on one surface (front surface) of the circuit board 11.
The circuit board 11 may also be a double-sided mounting type in
which the electronic components are mounted on both sides.
The circuit board 11 has a substantially rectangular shape, and a
plurality of connection through holes (not shown) are provided at
predetermined positions. These connection through holes are used
for connecting the electronic components to the conductive circuit,
and the electronic components are connected to the conductive
circuit in the connection through holes by a known method such as
soldering.
In the present embodiment, of the plurality of electronic
components, only the inductors 20 are shown, and other electronic
components are not shown.
Inductor 20
The inductors 20 used in the present embodiment have a coupled
inductor structure, and include a pair of coils 21 each formed by
winding a winding wire, and a magnetic core 30 (see FIGS. 5 and
6).
Coil 21
Each coil 21 is an edgewise coil 21 formed by winding a rectangular
wire (an example of a winding wire) in an edgewise shape and in an
annular shape. The coil 21 includes a winding portion 22 made by
winding a winding wire to form a cylindrical shape as a whole, and
a pair of lead terminals 23 that extends from both ends in the
axial direction L of the winding portion in the same direction
(downward) and in parallel to each other, and is connected to the
conductive circuit.
Magnetic Core 30
The magnetic core 30 is formed by combining a pair of a first core
30A and second core 30B having the same shape and size. The first
core 30A and the second core 30B each have a substantially oval
thick plate-like bottom wall portion 31, and are arranged so that
the bottom wall portions 31 face each other.
A pair of columnar side legs 32 extending toward the mating core is
provided at both ends in the longitudinal direction of one bottom
wall portion 31. Also, a plate-like central leg 33 is provided at
the center of the bottom wall portion 31, and extends along the
short side direction toward the mating core. As shown in FIG. 5, in
the state where the winding portion 22 of the coil 21 is arranged
around the side leg 32, the central leg 33 becomes thicker towards
its end portion, so that it extends along (parallel to) the side
surface 22A of the winding portion 22. In addition, the regions
where the lead terminals 23 are arranged in the end portions of the
central leg 33 are escape portions 34 that are cut out to make room
for the lead terminals 23 (see FIG. 6).
The rising dimension (height) of the side leg 32 and the central
leg 33 from the bottom wall portion 31 is set so that the side leg
32 is slightly longer. In this manner, in the state where the pair
of first core 30A and second core 30B are combined, a gap is formed
between the end surfaces of the central legs 33 facing each
other.
The inductor 20 has a configuration in which a pair of coils 21 are
arranged side by side so that the axes of the winding portions 22
are parallel and horizontal, and the coils 21 are held together by
the magnetic core 30 (the first core 30A and the second core
30B).
In this assembled state, the winding portions 22 of the pair of
coils 21 are disposed around the side legs 32 of the first core 30A
and the second core 30B, respectively. Also, two pairs (four) of
lead terminals 23 of the pair of coils 21 are extended in the same
direction (downward in FIG. 6) while avoiding interference with the
magnetic core 30 by the escape portions 34 of the magnetic core 30.
The central leg 33 is disposed between the pair of coils 21
arranged side by side. In this state, the end surfaces of the pair
of the central legs 33 facing each other are disposed apart from
each other, and a gap is formed between them.
Note, that in this state, the coil 21 and the magnetic core 30 are
not relatively positioned, and the winding portion 22 of the coil
21 is disposed to be freely movable around the side leg 32 of the
magnetic core 30.
Heat Sink 40
The heat sink 40 is disposed on the lower surface of the circuit
board 11. The heat sink 40 is a heat dissipation member made of a
metal material having excellent heat conductivity such as aluminum
or an aluminum alloy, and dissipates heat generated in the circuit
board 11.
An upper surface 40A of the heat sink 40 has a substantially flat
plate shape, and the circuit board 11 is disposed at a
predetermined position thereon via an insulating sheet 50. The
insulating sheet 50 has an adhesive property that can be fixed to
the circuit board 11 and the heat sink 40.
As shown in FIGS. 5 and 7, escape recesses 41 that are recessed
downward from the upper surface 40A and can accommodate the lead
terminals 23 of the coils 21 are provided in a region of the upper
surface 40A of the heat sink 40, in which the above inductors 20
are disposed.
Also, in the upper surface 40A of the heat sink 40, receiving
protrusions 42 that protrude upward from the upper surface 40A and
that are in heat transfer contact with the winding portions 22 are
provided in regions where the winding portions of the coils 21 are
disposed. Each receiving protrusion 42 has a substantially
quadrangular prism shape, and its upper surface 42A (the surface
facing the winding portion 22) is curved along a side surface 22A
that extends along the axis of the winding portion 22, as shown in
FIG. 9.
The protruding dimension of the receiving protrusion 42 from the
upper surface 40A of the heat sink 40 is set to be larger than the
thickness of the circuit board 11. With this configuration, in the
state where the circuit board 11 is disposed at the predetermined
position of the upper surface 40A of the heat sink 40, the
receiving protrusions 42 penetrate the board side through holes 12
in the circuit board 11 and protrude upward from the upper surface
of the circuit board 11, approaching the winding portions of the
coils 21. Note, that if the circuit board is a double-sided
mounting type, the receiving protrusion protrudes further upward by
an amount corresponding to the dimensions of the electronic
components mounted on the back surface of the circuit board.
Furthermore, in the present embodiment, in the state where a frame
60 described later is positioned with respect to the circuit board
11, the protrusion dimension of the receiving protrusion 42 is set
to such a dimension that it penetrates a bottom wall 67 of a
subframe 63 described later and protrudes upward from the bottom
wall 67, and that it can contact the side surface 22A of the
winding portion 22.
Note, that escape holes (not shown) are provided through the
insulating sheet 50 at positions corresponding to the escape
recesses 41 and the receiving protrusions 42.
In addition, a large number of plate-like fins 43 extending
downward are provided on the lower surface of the heat sink 40.
Frame 60
The frame 60 is made of synthetic resin, and has a substantially
rectangular outer frame 61 as shown in FIGS. 10 and 12.
On one side of a pair of outer first side walls 61A extending in
the short side direction of the outer frame 61, a terminal block 62
for positioning and accommodating a plate-like terminal for
connection to an external terminal (not shown) protrudes inward.
Also, the subframe 63 is provided integrally with the outer frame
61 at positions where the inductors 20 are disposed in the frame
60. In the present embodiment, two inductors 20 are provided side
by side, and the subframe 63 has an elongated rectangular shape
that surrounds the inductors 20 and fits the inductors 20 almost
entirely inside.
One side (the right side in FIG. 10) of the pair of inner first
side walls 63A extending in the short side direction of the
subframe 63 is formed integrally with the outer frame 61. On the
other hand, the inner first side wall 63A on the other side (the
left side in FIG. 10) is provided with a pair of bridging portions
64 extending outward, and is formed integrally with the terminal
block 62.
Inside the subframe 63, a partition wall 65 that divides the inner
region into two is provided. A pair of regions surrounded by the
partition wall 65 and the subframe 63 are a first accommodation
portion 66A and a second accommodation portion 66B into which the
two inductors 20 are fitted.
As shown in FIG. 5, the subframe 63 includes bottom walls 67 that
continue to the lower end of the subframe 63. Near the pair of side
edges, of bottom walls 67, extending in the longitudinal direction
(near the side edges extending in the left-right direction in FIG.
11), core receiving portions 73 each having a shape extending along
the side surface 31A of the bottom wall portion 31 of the magnetic
core 30 are provided that rise from the bottom walls 67, when the
inductors 20 are accommodated in the accommodation portions 66A and
66B.
Also, terminal through holes 72 for passing through the lead
terminals 23 are provided at positions of the bottom walls 67
corresponding to the lead terminals 23, in the state where the
inductors 20 are accommodated in the accommodation portions 66A and
66B. Each terminal through hole 72 has a tapered shape in which the
hole edge on the upper end side expands outward.
Furthermore, rectangular frame side through holes 74 for passing
through the receiving protrusions 42 provided on the heat sink 40
are provided at positions of the bottom walls 67 corresponding to
the winding portions 22, in the state where the inductors 20 are
accommodated in the accommodation portions 66A and 66B. Each frame
side through hole 74 has a diameter that is slightly larger than
that of the receiving protrusion 42 (see FIG. 5).
Also, at the four corners of the bottom wall 67 of each of the
first accommodation portion 66A and the second accommodation
portion 66B, overhanging portions 68 that overhang inward and
extend in the vertical direction are provided (see FIG. 11). In the
state where the inductors 20 are accommodated in the accommodation
portions 66A and 66B, these overhanging portions 68 are in contact
with the side surfaces of the magnetic cores 30 to reduce rattling
of the inductors 20 in the accommodation portions 66A and 66B (see
FIG. 2).
Note, that the subframe 63 has such a height that it can
accommodate up to the top surface of the inductor 20, and is higher
than the outer frame 61 and protrudes upward from the outer frame
61 (see FIGS. 3 and 4).
As shown in FIG. 12, legs 69 protruding downward are provided on
the lower surface of the four corners of the outer frame 61. In
addition, positioning projections 70 that protrude toward the heat
sink 40 (downward) are provided next to the pair of legs 69 of the
outer first side wall 61A on which the terminal block 62 is
provided. These positioning projections 70 are fitted into
positioning recesses 44 provided on the upper surface 40A of the
heat sink 40, whereby the frame 60 is positioned with respect to
the heat sink 40.
As shown in FIG. 5, in the assembled circuit assembly 10, the
receiving protrusions 42 of the heat sink 40 penetrate the board
side through holes 12 of the circuit board 11 and the frame side
through holes 74 of the bottom walls 67 of the subframe 63 and
protrude to the upper surface side of the bottom walls 67, and are
in contact with the side surfaces 22A of the winding portions 22 of
the coils 21 that are arranged such that the axes are along the
circuit board 11.
Operation and Effect
The circuit assembly 10 of the present embodiment has the above
configuration, and its operation and effect will be described
next.
In the present embodiment, the board side through holes 12 are
provided in the regions of the circuit board 11 corresponding to
the coils 21 of the inductors 20. Also, in the regions of the heat
sink 40 corresponding to board side through holes 12, the receiving
protrusions 42 penetrate the board side through holes 12 and
protrude to the surface side of the circuit board 11 on which the
inductors 20 are disposed, and are in heat transfer contact with
the winding portions 22 of the coils 21.
With this configuration, the receiving protrusions 42 provided on
the heat sink 40 protrude from the through holes of the circuit
board 11. Accordingly, the receiving protrusions 42 can be in heat
transfer contact with the coils 21 at the positions close to the
coils 21, which are heat generation members. As a result, the heat
generated from the coils 21 and the magnetic cores 30 can be
efficiently transferred to the heat sink 40, and can be dissipated
to the outside.
Also, each coil 21 is disposed so that the axis of the winding
portion 22 extends along the circuit board 11, and the receiving
protrusion 42 is formed along the side surface 22A that extends
along the axis of the winding portion 22, and is in contact with
the side surface 22A of the winding portion 22.
In the configuration in which the coil 21 is arranged vertically
with respect to the circuit board 11, the area required for the
coil 21 on the circuit board 11 can be reduced, compared to a
configuration in which the coil 21 is disposed in the direction in
which the axis of the winding portion 22 intersects the circuit
board 11. As a result, the circuit assembly 10 can be made more
compact.
In addition, because the receiving protrusion 42 is shaped along
the side surface 22 along the axis of the winding portion 22 of the
coil 21 arranged vertically, even if the side surface 22A is not
flat, the entire facing surface (the upper surface 42A) can be
arranged close to the side surface 22A. Accordingly, the circuit
assembly 10 is excellent in heat dissipation.
In the vertically arranged coil 21, if the side surface 22A of the
winding portion 22 is not flat, there is a concern about rattling
due to vibration, compared to the horizontally arranged coil.
However, the receiving protrusion 42 that is shaped along the side
surface 22A of the winding portion 22 can stably support at least a
part of the winding portion 22 from the circuit board 11 side.
Therefore, rattling of the coil 21 can be reduced.
As described above, according to the present embodiment, a circuit
assembly 10 that has excellent heat dissipation can be
obtained.
Second Embodiment
Next, the second embodiment will be described with reference to
FIGS. 13 to 18. Hereinafter, only the structural aspects different
from the first embodiment will be described. The circuit board 11
and the inductor 20 are denoted by the same reference numerals as
those of the first embodiment. Also, for other compounds that are
the same as those in the first embodiment, a reference numeral
obtained by adding 40 to the reference numeral assigned to the
corresponding compound in the first embodiment is used.
A circuit assembly 120 of the present embodiment is different from
that of the first embodiment in the form of receiving protrusions
82 provided on a heat sink 80. As shown in FIGS. 15 and 16, in the
regions where the pair of magnetic cores 30 (the first cores 30A
and the second cores 30B) are disposed on the upper surface 80A of
the heat sink 80, receiving protrusions 82 that protrude upward
from the upper surface 80A and that are in heat transfer contact
with the first core 30A and the second core 30B are provided (four
in total). Each receiving protrusion 82 has a plate shape rising
from the upper surface 80A of the heat sink 80, and its upper
surface 82A (the surface facing the magnetic core 30) is cut out in
a substantially trapezoidal shape and extends along a side surface
31A of a bottom wall portion 31 of the magnetic core 30, as shown
in FIG. 14.
The protruding dimension of the receiving protrusion 82 from the
upper surface 80A of the heat sink 80 is set to be larger than the
thickness of the circuit board 11. With this configuration, in the
state where the circuit board 11 is disposed at the predetermined
position of the upper surface 80A of the heat sink 80, the
receiving protrusions 82 penetrate the board side through holes 12
of the circuit board 11 and protrude upward from the upper surface
of the circuit board 11, approaching the winding portions of the
pair of magnetic cores 30.
In the state where a frame 100 described later is positioned with
respect to the circuit board 11, the protruding dimension of the
receiving protrusion 82 is set to such a dimension that it
penetrates a bottom wall 107 of a subframe 103 described later and
protrudes upward from the bottom wall 107, and that it can contact
a side surface 31A of a bottom wall portion 31 of the magnetic core
30.
Frame 100
The frame 100 of the present embodiment is different from that of
the first embodiment in the form of the subframe 103.
In the present embodiment, of core receiving portions 113 provided
on the bottom walls 107 of the subframe 103, in a region near the
pair of inner second walls 103B extending in the longitudinal
direction of the subframe 103, frame side through holes 114 are
provided for disposing the above receiving protrusions 82 in a
first accommodation portion 106A and a second accommodation portion
106B. The frame side through holes 114 are for disposing the
receiving protrusions 82 provided on the heat sink 80 in the first
accommodation portion 106A and the second accommodation portion
106B, and each have a diameter through which the receiving
protrusion 82 is inserted (see FIG. 17).
Also, in the present embodiment, heat dissipation through holes 115
are provided at positions corresponding to the winding portions 22,
in the state where the inductors 20 are accommodated in the
accommodation portions 106A and 106B in the bottom walls 107.
Furthermore, in the circuit board 11, areas corresponding to the
heat dissipation through holes 115 of the frame 100 are provided
with board side heat dissipation through holes (not shown).
As shown in FIG. 14, in the assembled circuit assembly 120, the
upper surfaces 82A of the receiving protrusions 82 of the heat sink
80 are disposed in the accommodation portions 106A and 106B through
the board side through holes 12 of the circuit board 11 and the
frame side through holes 114 provided on the core receiving
portions 113 of the subframe 103. As a result, the receiving
protrusions 82 are in contact with the side surfaces 31A of the
bottom wall portions 31 of the magnetic cores 30.
In this state, the upper surfaces of the core receiving portions
113 of the frame 100 and the upper surfaces 82A of the receiving
protrusions 82 of the heat sink 80 are flush with each other, and
the core receiving portions 113 and the receiving protrusions 82
support the magnetic cores 30 (see FIG. 14).
In the circuit assembly 120 according to the present embodiment,
the board side through holes 12 are provided in regions of the
circuit board 11 corresponding to the magnetic cores 30 of the
inductors 20. Also, in regions of the heat sink 80 corresponding to
the board side through holes 12, receiving protrusions 82 are
provided, which penetrate the board side through holes 12, protrude
the surface side of the circuit board 11 on which the inductors 20
are disposed, and are in heat transfer contact with the side
surfaces 31A of the bottom wall portions 31 of the magnetic cores
30.
Accordingly, the receiving protrusions 82 provided in the heat sink
80 protrude from the circuit board 11, and can be in heat transfer
contact with the magnetic cores 30, which are the heat generation
members, at positions close to the magnetic cores 30. As a result,
the heat generated from the coils 21 and the magnetic cores 30 can
be efficiently transferred to the heat sink 80, and can be
dissipated to the outside.
Other Embodiments
The technique disclosed in the present specification is not limited
to the embodiments described with reference to the above
description and the drawings, and for example, the following
embodiments are also included in the technical scope.
In the above embodiments, the receiving protrusions 42 or 82
protruding through the circuit board 11 are in contact with the
winding portions 22 or the bottom wall portions 31. However, a
configuration may also be employed in which both the receiving
protrusions 42 and 82 are provided on the heat dissipation plate to
contact both the winding portions 22 and the magnetic cores 30.
In the above embodiments, the upper surface 42A (82A) (the facing
surface) of the receiving protrusion 42 (82) extends along the side
surface 22A of the winding portion 22 (the side surface 31A of the
bottom wall portion 31). However, the upper surface 42A (82A) of
the receiving protrusion 42 (82) does not necessarily have to
extend along the side surface 22A of the winding portion 22 (the
side surface 31A of the bottom wall portion 31). It is sufficient
that the upper surface 42A (82A) of the receiving protrusion 42
(82) is in heat transfer contact with the side surface 22A of the
winding portion 22 (the side surface 31A of the bottom wall portion
31).
In the above embodiments, a filler such as grease or a heat
dissipation agent may also be provided between the receiving
protrusions 42 (82) and the winding portions 22 (the bottom wall
portions 31). Alternatively, a cushioning material such as a heat
dissipation sheet may also be provided. With this configuration,
even if there is a gap due to tolerance between the winding portion
22 (the bottom wall portion 31) of the coil 21 and the upper
surface 42A (82A) of the receiving protrusion 42 (82), both of them
can be reliably brought into heat transfer contact. As a result, a
circuit assembly having an even better heat dissipation effect can
be obtained.
In the above embodiments, an adhesive agent may also be provided
between the receiving protrusions 42 (82) and the winding portions
22 (the bottom wall portions 31). With this configuration, even if
there is a gap due to tolerance between the winding portion 22 (the
bottom wall portion 31) of the coil 21 and the upper surface 42A
(82A) of the receiving protrusion 42 (82), both of them can be
reliably brought into heat transfer contact, and can be
mechanically fixed. As a result, a circuit assembly that is more
excellent in heat dissipation effect, impact resistance, and
vibration resistance can be obtained.
The bottom walls 67 and 107 that are provided on the subframes 63
and 103 may also be omitted.
The receiving protrusions 42 and 82 are configured to be in heat
transfer contact with the coils 21 of the magnetic cores 30 of the
inductors 20. However, the receiving protrusions can be used for
receiving components that are accommodated in an insulating case.
The receiving protrusions can be used for receiving choke coils
accommodated in the case, for example.
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